Resilient Integrated Photonic Transport In Denied Environments (RIPTIDE)

Future autonomous operations will occur in contested electromagnetic environments where traditional positioning, navigation, and timing (PNT) references cannot be assumed. Radio frequency (RF) emissions are inherently detectable, direction-findable, and susceptible to interference and spoofing. These properties are extensively characterized in the open engineering and civil aviation safety literature. Distributed autonomous systems still need to execute coordinated maneuver, distributed sensing, collaborative targeting, long-range autonomy, and mesh-networked operations under these conditions. Inertial navigation accumulates drift over long-duration sorties. RF cooperative navigation can be detected and jammed. Existing free-space optical terminals often exceed Group three (3) UAS size, weight, and power (SWaP) constraints. The needed capability is an ad hoc PNT network, or distributed navigation transport layer, in which the optical mesh serves simultaneously as a data transport layer and as a distributed navigation sensor. Each photonic inter-UAS crosslink provides high-capacity coherent optical communications, two-way precision time transfer, precision optical direction finding, and ranging. Adjacent nodes exchange state vectors, time-transfer references, optical angle measurements, range measurements, and navigation corrections, and a distributed estimator fuses these optical measurements with local inertial data to constrain relative geometry and suppress drift. Anchor nodes operating within visual navigation range of land provide absolute position, bearing, and time references, and these references propagate hop by hop through an optical relay chain to nodes operating over featureless open water. The required capability is defined at the scale of the full swarm, with the formation-level requirement taking precedence over any single link. The swarm shall maintain a navigation accuracy of eight (8) to eleven (11) meters circular error probable (CEP), or better, at the most distant node of a distributed formation spanning two hundred (200) to three hundred (300) nautical miles over feature-sparse terrain, with the formation anchored to land-based references at one end and extending beyond visual navigation range at the other. A representative relay geometry uses approximately eight (8) to twelve (12) optical hops with per-hop ranges of twenty (20) to thirty (30) nautical miles. Proposers may trade hop count against per-hop range, provided the architecture closes the full formation span and meets the formation-level CEP requirement. The architecture shall maintain a shared, formation-wide navigation solution across all nodes in the chain, shall bound error growth across successive hops such that accumulated drift at the seaward edge of the formation remains within the formation-level accuracy requirement stated above, and shall preserve formation coherence under the loss of individual nodes or links within the chain. Candidate payload architectures should provide broad angular coverage within Group three (3) UAS SWaP constraints, including multi-sector optical apertures combining wide-field acquisition sensing (tens of microradians of precision after approximately 1 second of integration) with high-bandwidth photonic beam steering and coherent detection for navigation-grade closed-loop tracking (sub-microradian angular resolution in less than 1 millisecond). As a part of this feasibility study, the proposers shall address all viable overall system design options with respective specifications on the key system attributes, including link budget and range, acquisition and tracking precision, time-transfer accuracy, ranging accuracy, distributed estimation architecture, payload SWaP, and robustness to atmospheric attenuation, atmospheric ducting, turbulence, link interruption, and node loss.